Electrolysis aqueous

• Aqueous solutions are dissolved in water and are usually colourless
• Aqueous solutions have a substance dissolved in water e.g salt solutions
• Water molecules ionise(split) forming hydrogen ions and hydroxide ions

  Shown here:

  
• It’s important that the electrodes don’t react with the chemicals that are being made in elecrolysis. Electrodes are inert and platinum is often used as an electrode as it is an unreactive metal
• Example of electrolysis aqueous solution - copper sulphate solution 


  The copper ion( positive) and the H+ ion are both attracted to the cathode. To find out which ion is reduced ( reduction) at the cathode there’s a rule:

  Hydrogen is produced at the cathode if the metal is more reactive than hydrogen.

  if no halide ions are present, then the hydroxide ions are discharged and oxygen is formed at the anode. if both ions are present then a halogen is formed at the anode. in this case there are only sulphate ions and hydroxide ions so oxygen is formed at the anode

  
• oxygen atoms, hydrogen atoms, nitrogen atoms and group 7 atoms pair to form a molecule